The invention relates to a method and apparatus for remote control by means of transmitting coded commands from a transmitter to a receiver in which the respective interval time span between a first energy impulse, starting the transmission, and a second energy impulse concluding the transmission is utilized as code for identifying the individual command.
Such a method for remote control is described in the German Offenlegungsschrift No. 2,554,637. The time intervals allotted to the commands of the command inventory provided in aggregate for the remote control are staggered differently such that in a command inventory having a total of n commands (n-1) total differences can be formed from the n established intervals which are assigned to said commands, said intervals having the same value. Indeed, a rigidly prescribed integral number p from the multitude of integral numbers 1 . . . n is assigned to each command provided in the command inventory whereby p represents a particular value for each command. Then, during the transmission of the p-th command, the final impulse must not be emitted earlier than at the point in time EQU t.sub.p =A+(p-1)a (1)
and not later than at the point in time EQU T.sub.p =A+p.multidot.a (2)
after the occurrence of the starting impulse so the command can be identified on the receiver side. Therefore, a and A are constant time values, whereby A can also obviously have the value .phi.. The tolerance permissible for the transmission is formed by the differential T.sub.p -t.sub.p =a. Said tolerance obviously has the same value of a for all commands.
Therefore, however, the required technical expense rises considerably for the synchronization of the circuits responsible for the time interval between the starting impulse and final impulse on the transmitter side and circuits recognizing the number p and thus the transmitted command on the receiver side. This requires a considerable increase in production costs which one should like to avoid, particularly in simpler devices of this type such as in the toy industry. On the other hand, nevertheless one is interested in sufficient operational safety for the device.